Gaseous fuel mixtures



Patented July 4, 1950* No Drawing. Application July 15, -1'947,-SerialN0. 761,158. In- Great Britain April 24, 1947 1 Claim. (o1. 48-197) Thisinventionrelates to gaseous fuel mixtures and more. particularlyto suchfuel mixtures that have a high calorific value and a low ignition point.

Fuel mixtures of this type are in .demand for use in metallurgical andother. industrial operations in which an intense local heat is required,as forinstance inputting metals, hardening and annealing, scarfing,melting. and welding metals and the working of lead, hard glass andsilica- For these purposes, the oxy-acetylene and oXyhydrogen flameshave been widely used but both are comparatively expensive, and in thecase of acetylene, because of high carbon content and critical nature ofthe flame, unless great precau tions in use are observed, it is liableto be dangerous and costly and work may be spoiled.

It is an object of the present invention to provide a cheap gas mixtureby raising the calorific value and lowering the ignition point of theordinary fuel gas, such as coal gas and natural (petroleum) gas suppliedfor general public use which will be referred to hereinafter as citygas.

The gas mixture may be made in the first instance and compressed incylinders and used direct from the cylinders to the burner.Alternatively, the supplementary gaseous material required to raise thecalorific value and lower the ignition point of the city gas may beobtained from material compressed in cylinders and supplied from thecylinder to the city gas in pipe lines by means of suitable flow meters.

Various proposals with the above object in view have been made hithertoincluding the addition of ethyl ether to give a vapour content of thecity gas from 2.5 to 5% by volume. There are, however, diflicultiesinvolved in making a gas mixture as above described from, for example,ordinary city gas by making additions to raise the calorific value andlower the ignition point and produce a gas which is comparable for thepurposes above described with acetylene. Suitable materials for additionare necessarily of an easily condensable character, such as the higherhydrocarbons and gas mixtures supplied in the usual city mains consistmainly of the more permanent gases, of which hydrogen, carbon monoxideand methane are examples. When substances are added with a view toincrease the calorific value and lower the ignition point, in many casessuch substances condense under pressure in the cylinders, and when thecylinder is opened to supply a burner, direct or through factory pipelines, imperfect diffusion of the conburner,

stream of gasmeetsthe oxygen supply there may stituent gases may occurand a homogeneous gas,

such as acetylene; will not be supplied to the Moreover, when therapidly moving be also imperfectdifiusion with consequent deleteriouseifects upon the intensity of the flame and its resulting temperatures.

It hasnow been found possible by proper selection of the-added materialand the proportions inwhich it is used to produce a gas mixture which,whether used from cylinder or formed in the pipe line by introducingcompressed material from a cylinder, will give a homogeneous mixture atthe point at which ignition occurs and which may be used with oxygen inthe same way as acetylene and produce comparable results and in somerespects even improved results.

According to the present invention a gaseous fuel mixture consists incity gas, propane and a mixture of petroleum ether and ethyl ether inthe proportions of the said ingredients being as follows when the citygas is coal gas:

City gas at F. and atmospheric pressure,

approximately -600 cubic feet Propane, approximately 5-9 lbs.

Petroleum ether and ethyl ether mixture, ap-

proximatel 1 lb.

and when the city gas is natural gas, half the proportions of propaneand petroleum ether and ethyl ether mixture.

The petroleum ether referred to is the petroleum fraction having aboiling point range from approximately 40 C. to 60 C. at atmosphericpressure, such, for example, as benzin.

Other petroleum ethers with higher boiling points may be used in theproportions stated, provided means are employed to vaporize the materialsufi'iciently for proper diffusion with the city gas before ignitionoccurs.

The propane above referred to is not necessarily the chemically purepropane,'but may also be the propane fraction obtained in the refiningof crude oil and containing butane with traces of other hydrocarbons,such as propylene, pentane and hexane.

Where ethyl ether and coal or natural gas are used in admixturedifiiculty is encountered in that imperfect diifusion of the ether inthe city gas may occur and precipitation may occur in pipe lines andregulators so that a flame of varying and uncertain composition andintensity is produced. The addition of propane with small amounts or" amixture of petroleum ether and ethyl ether results in a constant flow ofgases in the proportions hereinbefore stated and also results in aconstant and dependable intensity of city gas enables it to be used inlike manner to acetylene for the purposes hereinbefore enumerated and ithas been ascertained that lesser proportions than those given above areineffective, while larger proportions than the maximum specified aboveprovide no additional advantages.

Although a certain specific embodiment of the invention has been shownand described, it is obvious that many modifications thereof arepossible. The invention, therefore, is not to be restricted exceptinsofar as is necessitated by the prior art and by the spirit of theappended claim.

That which is claimed, as new, is:

A gaseous fuel mixture having a high calorific value and a low ignitionpoint, which mixture comprises city gas as herein defined, propane and amixture of petroleum ether and ethyl ether,

said petroleum ether being a petroleum fraction boiling over the rangeof C. to C., said mixture being in the proportion of approximately 5-9lbs. of propane and approximately 1 lb. of the mixture of petroleumether and ethyl ether for approximately 100-600 cubic feet at F. andatmospheric pressure of the city gas.

SAMUEL H. WHITE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,565,933 Harris Dec. 15, 19251,584,291 Harris May 11, 1926 1,596,729 Harris Aug. 17, 1926 2,305,752White Dec. 22, 1942 2,411,759 Seley Nov. 26, 1946 2,411,769 White Nov.26, 1946 OTHER REFERENCES The Science of Petroleum, Dunstan, editor,Oxford Univ. Press, London 1938, vol. I, pages '7 and 12.

Ll-Iackhs Chemical Dictionary, by Hackh, 2nd edition publishedBlakistons Son Inc., Philadelphia, 137, page 698.

